Ash Ketchum has traveled with many different companions during his Pokémon journey, from the ever-present Brock to his newest friend Goh, but none of them have complimented his character as much as May did.
While less lauded than some of her contemporaries, like Misty and Serena, the Hoenn native has a decidedly unique arc for the main character of a Pokémon series -- and not just because she was the first departure from the status quo the show had ever seen.
Much like the protagonist in the games, May is the daughter of the Petalburg Gym Leader, Norman, and has long been expected to follow in her father's battling footsteps. However, May isn't exactly keen on this idea, as both the pressure, and her own initial dislike of Pokémon make the prospect of becoming a trainer unappealing. Combatting this is her love of traveling; she demonstrates this love many times over the series when she pretends to host her own travel show -- much to the annoyance of her little brother, Max. Unfortunately for her, the only way to travel the world at age 10 is to become a Pokémon trainer.
Like Misty before her, May's first meeting with Ash ends in Pikachu torching her bike, and she eventually chooses the cute chick Pokémon Torchic as her starter. What results is a very welcome role reversal from previous series that caps off Ash's character arc through the first three regions, going from a complete Pokémon noob to slowly teach May all the things he's learned throughout his journey.
After five seasons of watching Ash make mistakes and learn from them, putting him in the role of a semi-experienced mentor not only fits but can even be played for laughs as he messes up mentorship. While May quickly realizes that Ash's style of training and battling is not for her, she still learns plenty from him by watching him battle, paying attention to what he does right and wrong.
Thus, it is through Ash that she slowly starts to become more comfortable around both Pokémon and battles, without ever going so far as to fall in love with battling. Soon she finds herself questioning what it is she really wants -- until she sees a Contest. Built around the innate appeal of various Pokémon, whether cool, beautiful or strong, Contests allowed her to emphasize her creativity by coming up with new and innovative moves, while simultaneously making her Ash's first companion with a concrete goal that she could continue to work towards through the gathering of Ribbons, paralleling Ash's own quest for Gym Badges.
Creating conflict was, of course, May's little brother Max. Unlike his older sister, Max adores Pokémon and battling, which, when coupled with his fierce study of the subject, means he knows a lot more than his sister. As a result, May often did her best to put him in his place, or forged forward with her own plans in spite of or to spite his advice.
But for as much they got on each other's nerves, May's love for her little brother was clear, jumping to his aid without an ounce of hesitation as soon as there was any danger, such as in the movie, Lucario and the Mystery of Mew, when the Tree of Life's immune system attempted to eliminate the human "invaders."
May and Max's realistic relationship helps to set the traveling duo apart from more idealized characters like Clemont and Bonnie, ironically giving more weight to the love they share through the juxtaposition of sibling rivalry. It helped to establish the tone of the Advanced seasons, whereby shifting the majority of conflicts to May and Max, allowed both Ash and Brock to be the "mature" ones of the group. This created a lighthearted series with potential for massive highs and crazy-deep lows that wasn't afraid to do either.
While May would grapple with hubris, she would go on to not only come close to winning both the Hoenn and Kanto Grand Festivals (top eight and top four respectively) but garner a reputation for herself separate from her father's legacy: the Princess of Hoenn. Her journey alongside Ash allowed him to continue to mature as a trainer and changed up the status quo for the first time in the show's history, all while creating a satisfying arc for herself from reluctant trainer to Top Coordinator, and she should be remembered more for the good she did for the show.